Contrasting passive and transform margin tectonic history and sedimentation: insights from 3D numerical modelling and observations from the Atlantic

Passive and transform margins emerging during continental rifting and opening of oceanic basins are fundamental elements of plate tectonics. It has been suggested that inherited structures, variable plate divergence velocities and surface processes exert a first order control on the topographic, bathymetric and magmatic evolution and thermal history of these margins and related sedimentary basins. We conducted 3D thermo-mechanical numerical experiments with the code I3ELVIS coupled to surface processes modelling (FDSPM) to simulate the dynamics of continental rifting, continental transform fault zone formation and persistent oceanic transform faulting. Numerical modelling results allow to explain the first order observations from passive and transform margins, such as diachronous rifting, strain localization into individual oblique rift basins and the opening of structurally separate oceanic basins connected in an open marine environment. In addition, the models reproduce the rise of transform marginal ridges and submarine plateaus, continental crustal slivers within oceanic transforms and their interaction with erosion and sedimentation. Model results are compared and validated by seismic and well data from passive and transform margin segments of the Atlantic.